The present invention relates to a semiconductor device, a method of fabricating the same, and a pattern generating method.
In recent years, an insulating material having a relative dielectric constant of 3 or less has been used in an interlayer insulating film of a semiconductor integrated circuit substrate. As a result, there has been caused a problem that a barrier metal for a copper wiring formed in an interlayer insulating film is corroded by a residual gas, such as H2O, remaining in an insulating film, and thus the reliability of a semiconductor device is deteriorated. Normally, in the semiconductor fabricating process, before a process for forming a barrier metal is carried out, degassing processing is carried out for the residual gas. However, the degassing is carried out through a region in which a wiring trench is formed in the interlayer insulating film. Also, wiring inhibition regions formed upper and lower wiring layers, respectively, with respect to a wiring layer having an inductor formed therein so as to correspond in position to the inductor, a wiring inhibition region formed under a wiring layer having a pad portion for wire bonding formed therein so as to correspond in position to the pad portion for wire bonding, a redundancy region formed below a fuse, and the like exist in a semiconductor device having a multilayer interconnection formed therein. The coverage of a wiring pattern is extremely less in each of these regions, therefore many wiring trenches within the corresponding interlayer insulating film are not formed in such a region. Therefore, the degassing is not sufficiently performed from the interlayer insulating film through wiring trenches or via holes formed below the wiring trenches. As a result, there is encountered a problem that the residual gas remaining in this region corrodes the barrier metal of the wiring pattern to cause imperfect wiring conduction or imperfect via conduction, thereby deteriorating the reliability of the semiconductor device.
Now, a semiconductor device including moisture resistance rings is proposed as a conventional semiconductor device. In this semiconductor device, the multiple moisture resistance rings are formed, and are bridged at a plurality of height levels with conductor patterns extending along a chip periphery, thereby making it possible to block penetration of the moisture or gas from the outside. This conventional semiconductor device, for example, is disclosed in Japanese Patent KOKAI No. 2004-296843.
In addition, a semiconductor device in which in order to enhance a moisture resistance property by using seal rings surrounding a circuit formation portion, wiring trenches are formed in a plurality of interlayer insulating films, respectively, so as to surround the circuit formation portion along a periphery of a semiconductor chip, conductive layers made of copper or a material containing therein copper as a basic constituent are buried in the wiring trenches, respectively, through a first anti-diffusion film made of copper so as to be connected to each other, and a second anti-diffusion film made of copper is formed between a plurality of interlayer insulating films so as to be connected to the first anti-diffusion film made of copper is proposed as another conventional semiconductor device. This another conventional semiconductor device, for example, is disclosed in Japanese Patent KOKAI No. 2004-297022.
However, although in the conventional semiconductor devices disclosed in Japanese Patent KOKAI Nos. 2004-296843 and 2004-297022, respectively, the penetration of the moisture or gas from the outside of the semiconductor device can be blocked by the moisture resistance wings or the like, it is impossible to prevent the imperfect wiring conduction or the imperfect via conduction from being caused due to the residual gas generated inside the moisture resistance rings or the like.